Unusual presentation of more common disease/injury

CASE REPORT

Bilateral psoas abscess during pregnancy presenting as an acute abdomen: atypical presentation Aruna Nigam,1 Anupam Prakash,2 Puja Pathak,3 Pooja Abbey4 1

Department of Obstetrics and Gynaecology, Hamdard Institute of Medical Sciences and Research, New Delhi, India 2 Department of Medicine, Lady Hardinge Medical College, New Delhi, India 3 Department of Obstetrics and Gynaecology, Lady Hardinge Medical College, New Delhi, India 4 Department of Radiology, Lady Hardinge Medical College, New Delhi, India

SUMMARY Nearly half of skeletal tuberculosis patients have spinal tuberculosis, but psoas abscess develops in only 5% of spinal tuberculosis cases. However, bilateral psoas abscess is a rarity. Psoas abscess occurring in pregnancy could be a clinical dilemma and is hardly reported. We report an unusual presentation of bilateral psoas abscess in pregnancy presenting as an acute abdomen and adnexal mass.

BACKGROUND Correspondence to Dr Aruna Nigam, [email protected]

Spinal tuberculosis is commonly encountered in tropical countries. Although unilateral tuberculous psoas abscess has been reported but bilateral psoas abscess is a rarity.1 An interesting clinical scenario in pregnancy of ‘bilateral psoas abscess mimicking acute abdomen and adnexal mass’ is being reported. There is no such case reported in the literature to date.

CASE PRESENTATION A 24-year-old primigravida at 13 weeks of gestation presented with severe pain in the lower abdomen for 1 week. Mild degree of pain in the lower abdomen and back was present since the time of conception. There was no history of pain during micturition, constipation or diarrhoea, trauma, fever, anorexia or weight loss. Abdominal examination revealed a suprapubic lump of 16–18 weeks size. Vaginal examination revealed 12–14 weeks size uterus deviating to the left side and a tender, 10×15 cm cystic mass with restricted mobility felt through the right fornix which was also extending anterior to the uterus.

Figure 1 Coronal T2 fat-suppressed MRI reveals altered signal intensity involving the L5/S1 vertebral bodies along with involvement of the intervertebral disc (thin white arrow). Thick white arrows denote the craniocaudal extent of the psoas abscess bilaterally.

DIFFERENTIAL DIAGNOSIS The differential diagnosis of twisted ovarian cyst and pedunculated twisted fibroid was made in view of the adnexal mass.

INVESTIGATIONS

To cite: Nigam A, Prakash A, Pathak P, et al. BMJ Case Rep Published online: [ please include Day Month Year] doi:10.1136/ bcr-2013-200860

Investigations revealed haemoglobin 10.4 gm/dL, total leucocyte count 10 000/mm3, differential leucocyte count P50 L30 M18 E2, erythrocyte sedimentation rate (ESR) 48 mm and CA-125 11 IU/L. Liver and kidney function tests and plasma sugar levels were normal. An emergency ultrasonography revealed bilateral adnexal masses of 10×8 cm and 12×12 cm with variable echogenicity and septations and single live intrauterine fetus of 14 weeks. In view of suspicion of a large corpus luteal cyst in both the ovaries, MRI was performed that showed (figure 1) a bilateral large iliopsoas abscess (right>left).There was extensive marrow oedema of L5 and S1 vertebral bodies with L5/S1 discal abscess (figure 2). Large paraspinal abscess was seen extending from S1 to S3.

Nigam A, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-200860

Figure 2 Axial T2-weighted MRI showing the gravid uterus with the fetal head (thick white arrow) and large abscesses within the bilateral psoas muscles (thin white arrow). Bilateral common iliac vessels (black arrow) are displaced medially by these abscesses. 1

Unusual presentation of more common disease/injury The final diagnosis of tuberculosis of the L5–S1 vertebrae with bilateral psoas abcess with prespinal abcess and epidural abscess was made after the investigations.

TREATMENT The patient was started on antitubercular treatment (ATT) (rifampicin, isoniazid, ethambutol and pyrazinamide).

OUTCOME AND FOLLOW-UP Repeat abdominal sonography after 2 months of ATT showed regression in the size of the abscesses. At 38 weeks of gestation, the patient delivered a 2.5 kg female baby through a cesarean section performed for fetal distress.

DISCUSSION Tuberculosis poses a challenge to the whole world and continues to be a major public health problem in India, with an estimated prevalence of three million tuberculosis cases in India alone.2 Spinal tuberculosis is the most common type of skeletal tuberculosis, constituting nearly half of such cases. Interestingly, 5% of patients with spinal tuberculosis develop psoas abscess.3 Psoas abscess may be classified as primary or secondary depending on the presence or absence of the underlying disease. An underlying disease of the viscera lying in close relationship to the psoas muscle, can lead to a secondary psoas abscess, which might be the cause of a palpable mass in the fornices, as in our case. The most common reported cause of secondary psoas abscess is Crohn’s disease.4 However, in developing countries the commonest cause of secondary psoas abscess is tubercular osteomyelitis of the lumbar spine. Bilateral psoas muscle abscess is a rarity and represents less than 3% of secondary abscesses.5 Psoas abscess is rare during pregnancy and only a few cases are reported in the literature.6 However, bilateral psoas abscess presenting as an adnexal mass and acute abdomen during pregnancy is not reported before to the best of our knowledge. In most pregnancies in developing nations, backaches could be a routine occurrence due to ligament stretching, postural changes and calcium deficiency7; and this could prevent attention being focused on an underlying aetiology, making diagnosis of a psoas abscess unlikely; specially since it is insidious in onset and has a non-specific clinical presentation. However, pregnancy induced backache is unlikely at 14 weeks as in this case. Progressive local back pain for weeks to months with or without associated muscle spasm and rigidity should prompt the clinician to suspect a spinal cause for the abscess. In general, laboratory testing is non-specific. However, a complete blood count, ESR, C reactive protein, blood cultures and urinalysis may be helpful in diagnosing infection in non-pregnant patients but during pregnancy they are unlikely to be helpful. Plain radiographs may reveal underlying discitis or vertebral osteomyelitis in chronic lesions but abdominal radiographs are avoided during pregnancy; especially in early pregnancy. In a non-pregnant patient, the gold standard imaging modality is

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intravenous contrast-enhanced spiral CT.8 However, MRI is better than a CT at imaging the spinal canal and provides a more complete evaluation of the spinal pathology and is also safe during pregnancy as there is no risk of radiation exposure.9 The classical triad of fever, backache and limitation of hip joint movements secondary to psoas spasm is present in only 30% of patients with psoas abscess.10 Fever, weight loss and constitutional symptoms are encountered in less than 40% of the cases.8 The initial ultrasound in the present case was suggestive of bilateral complex adnexal masses with normal CA 125 value, presenting a diagnostic dilemma. Therefore, in tropical countries, it is important to keep at the back of one’s mind the possibility of an underlying psoas abscess in a pregnant woman with abdominal pain and backache despite normal neurological examination.

Learning points ▸ Psoas abscess should be considered as a differential diagnosis in pregnant patients from the tropics who present with lower abdominal pain and backache. ▸ MRI is safe as well as better than CT imaging of the spinal canal and provides a more complete evaluation of the spinal pathology during pregnancy. CT is unacceptable in pregnancy when there is an alternative MRI. ▸ Psoas abscess is characterised by triads of fever, backache and limitation of hip joint movements, but it is not commonly observed. Competing interests None. Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed.

REFERENCES 1 2 3 4 5

6 7 8 9 10

Goni V, Thapa BR, Vyas S, et al. Bilateral psoas abscess: atypical presentation of spinal tuberculosis. Arch Iran Med 2012;15:253–56. Prakash A. Tuberculosis: the scourge of mankind. Indian J Med Spec 2012;3:19–22. Roy S. Cold abscess in caries spine. J Indian Med Assoc 1969;53:240–4. Ricci MA, Rose FB, Meyer KK. Pyogenic psoas abscess—worldwide variation in etiology. World J Surg 1986;10:34–43. Gezer A, Erkan S, Erzik B, et al. Primary psoas muscle abscess diagnosed and treated during pregnancy: case report and literature review. Infect Dis Obstet Gynecol 2004;12:147. Kumar S, Malhotra N, Chanana C, et al. Psoas abscess in obstetrics. Arch Gynecol Obstet 2009;279:247–9. Katonis P, Kampouroglou A, Aggelopoulos A, et al. Pregnancy related low back pain. Hippokratia 2011;15:205–10. Nussbaum ES, Rockswold GL, Bergman TA, et al. Spinal tuberculosis: a diagnostic and management challenge. J Neurosurg 1995;83:243–7. Tomich EB, Della-Giustina D. Bilateral psoas abscess in the emergency department. West J Emerg Med 2009;10:288–91. Vaz AP, Gomes J, Esteves J, et al. A rare cause of lower abdominal and pelvic mass, primary tuberculous psoas abscess: a case report. Cases J 2009;2:182.

Nigam A, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-200860

Unusual presentation of more common disease/injury

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Nigam A, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-200860

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Bilateral psoas abscess during pregnancy presenting as an acute abdomen: atypical presentation.

Nearly half of skeletal tuberculosis patients have spinal tuberculosis, but psoas abscess develops in only 5% of spinal tuberculosis cases. However, b...
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